1. Field of the Invention
The present invention relates to a heat exchanger, and more particularly to a finned heat exchanger.
2. Description of the Background Art
As conventional finned heat exchangers, a spiral finned heat exchanger, a corrugated finned heat exchanger and so on are known.
The spirally finned heat exchanger is produced in such a way that a fin made of aluminum or iron material is wound spirally by means of a fin wrapping machine around the circumferential surface of parallel straight tube portions of a serpentine or zigzag tube made of copper or iron material with a predetermined pitch so that the outer peripheral edge of the fin assumes a cylindrical shape, and, thereafter, the wound fin is brazed to the circumferential surface of the tube. The corrugated finned heat exchanger is produced in such a way that a corrugated fin made of aluminum is secured to parallel straight tube portions of a serpentine or zigzag tube by fitting cutouts formed in the corrugated fins in the direction of the height of the corrugation onto the straight tube portions.
There are the following problems in the above-described heat exchangers. The spirally finned heat exchanger described above is not simple in terms of the operation of winding the fin and is inferior in quantity production. Furthermore, the fin winding machine has a restriction in that the outer diameter of the fin cannot be made small and the pitch of the fin cannot be made fine. Similarly, the corrugated finned heat exchanger is not simple in terms of operation and inferior in quantity production. Further, the pitch of the fin cannot be made fine from a viewpoint of the operation of fitting the fin onto the tube. Accordingly, there are problems in that these known heat exchangers are poor in quantity production and large in size, and have a small radiating surface of the fins in relation to the large size of the exchanger itself.
The present invention has been made to solve the above-described problems, and the object thereof is to provide a finned heat exchanger which is superior in quantity production, large in the radiating surface of the fins and compact in size.